For field managers, as well as field sales and service personnel, the ability to conveniently and rapidly transmit and/or receive messages to and from a central data base is essential. However, the mobile nature of these and many other occupations makes access to wireline terminals impractical, if not impossible. Modem wireless two-way messaging systems, such as commercial remote data terminal networks, are directed to supporting the mobile data messaging needs of such professionals as they travel about the coverage area of the messaging network. These networks typically operate within the frequency range reserved for cellular communications, and require a bandwidth on the order of 25 MHz.
Within such networks, users employ transportable field transceivers to contact one or more regional processors, and thereby gain access to the network and a central application host/database. Typically, as a user moves about the coverage area, signals traveling between the mobile and regional processors are subject to fading (i.e., random signal variations usually induced by atmospheric conditions and/or the surrounding topography). These variations can introduce bit errors into the data being passed to and from the mobile transceiver. The standard protocols and relatively unintelligent regional processors employed within the networks dictate that a substantial fixed portion of the transmission bandwidth be dedicated to error correction. This naturally reduces the bandwidth available to a user for sending and receiving information. The error correction afforded by this information bandwidth reduction is indeed necessary when a user is in an area where fading is evident. However, in an environment where fading is minimal or zero, successful transmission and reception of information can be accomplished with reduced error correction. If the percentage of bandwidth dedicated to error correction were to be dynamically adjusted in response to the relative fading a user was experiencing, the information bandwidth could be maximized. This type of dynamic bandwidth management is employed within certain facsimile machine protocols, so that if the telephonic connection between two facsimile machines is of high quality (i.e., induces minimal bit errors) the amount of error correction is reduced, and the bandwidth afforded to information transmission is increased. Unfortunately, current wireless two-way data networks are unable to employ dynamic bandwidth management. In order to accommodate dynamic variations in the information bandwidths of the field transceivers employed within a wireless two-way data network, the information bandwidths of the associated regional processors and central application host/database would have to be responsively varied in a similar dynamic manner. The transceivers, processors and protocols utilized within present wireless two-way data networks are simply not adapted to support such bandwidth dynamics.